It is desirable to communicate information between various locations within and around vehicles, including but not limited to cars, trucks and tractor-trailers, trains, ships and planes. Traditionally, this has been obtained by installing conductive wires between points. More recently, optical cable has somewhat similarly been employed in this role. Traditional wireless technologies in the 2.4 and 5 GHz frequency bands are also used.
Unfortunately all of these prior art systems have disadvantages. Wire and optical cable consume appreciable material and require routing between the various locations using the information, often entailing considerable design complexity. The conventional wireless technologies also often entail considerable design complexity, both to ensure that the integrity of the information is maintained against corrupting influence from outside the vehicle as well as to ensure that the energy being used to communicate the information does not become a corrupting influence on other systems.
These concerns are exacerbated in the context of vehicles. Firstly, a vehicle has particular structure. It has compartments, that is, spaces or cavities. These include large compartments, which are here termed “major compartments.” For example and without limitation, in a common automobile the major compartments are the engine or under-hood compartment, the passenger compartment, and the trunk or boot. In a common freight-hauling truck the major compartments are the engine compartment, driver/passenger compartment, and the cargo area. In common vehicles the glove box or other interior storage areas, for instance, are not major compartments. As a generalization, physical access to the major compartments of a vehicle is usually available. In contrast, physical access to the other compartments of a vehicle often is problematical.
Secondly, a vehicle is mobile by its very nature. Its systems therefore have the ability to be corruptingly influenced or to become a corrupting influence in highly varying and very difficult to predict manners. For an example, consider the traditional wireless technologies in the 2.4 or 5 GHz frequency bands. If a vehicle employing these is brought near sensitive electronic equipment it may cause disruption of that equipment. Conversely, the very same vehicle may itself be severely disrupted if brought near high powered electronic equipment. These concerns complicate information communication within (which we will regard here as including attached to the outside of) and in close proximity to vehicles.
Accordingly, what is needed are better systems for communications within and near to vehicles. Such systems should preferably have the capability for a single transmission to reach all of the vehicle compartments, as well as the near proximity outside the vehicle, without the use of repeaters or multiple physical access points.